KDX200/220 Jetting Database

[Jamie Kouk]

1996 KDX 200

200-1000 feet elevation

 

20 hour top end (wiseco)

EFM auto clutch

fmf gold series pipe 

Boyesen reeds

stock needle 2 clip from top

148 40 jets 

air screw at 2-2.5 turns out.

 

fouls like a bastard when riding slow doing trials type riding. Runs great in the fast single track. 

 

Any tips on getting it to run leaner at low speed. 

 

 

 

[OLHILLBILLY]

18 hours ago, Jamie Kouk said:

1996 KDX 200

200-1000 feet elevation

 

20 hour top end (wiseco)

EFM auto clutch

fmf gold series pipe 

Boyesen reeds

stock needle 2 clip from top

148 40 jets 

air screw at 2-2.5 turns out.

 

fouls like a bastard when riding slow doing trials type riding. Runs great in the fast single track. 

 

Any tips on getting it to run leaner at low speed. 

 

 

 

Did it just start fouling plugs? Been doing it for a while? Have you changed anything or did any work on it leading up to it? Jetting looks right (same as I had in mine), air screw is out farther than should be (mine was good at around 1-1.5 out with a 40 pilot). Could be any one of a few things, but need a little more background info.

[Jamie Kouk]

I dropped to the 148 from 152 and 40 from 42 last week. It ran great Monday Thursday and Friday. Now it's fouling. I check the spark and it's really weak. I'm thinking I might have an ignition problem. I ordered a coil today but will check the grounds tomorrow. 

[OLHILLBILLY]

23 hours ago, Jamie Kouk said:

I dropped to the 148 from 152 and 40 from 42 last week. It ran great Monday Thursday and Friday. Now it's fouling. I check the spark and it's really weak. I'm thinking I might have an ignition problem. I ordered a coil today but will check the grounds tomorrow. 

The coil went bad on my '04. Didn't foul plugs, but wouldn't start if the temperature was under 45 degrees. I made the mistake of soaking the carb body in Chem-Dip for a couple hours one time. It partially dissolved the main jet block gasket, causing it to run way rich no matter the jetting. That time it did foul plugs. Replaced the gasket, ran the next plug in it for over two years.

[Jamie Kouk]

Ok so I changed the coil and still a very weak spark. I took all the wiring apart looking for broken wires or corroded contact, nothing. Called a buddy who's son has a kdx and asked to borrow all his components to figure out what one failed. While waiting I tried a few other plugs with no luck until I put the shittiest random plug I found in a bin and full spark!!! It runs great!!!  Thanks for the help, I'm picking up a few spares tomorrow and do some test runs tomorrow night. ??

[OLHILLBILLY]

2 hours ago, Jamie Kouk said:

Ok so I changed the coil and still a very weak spark. I took all the wiring apart looking for broken wires or corroded contact, nothing. Called a buddy who's son has a kdx and asked to borrow all his components to figure out what one failed. While waiting I tried a few other plugs with no luck until I put the shittiest random plug I found in a bin and full spark!!! It runs great!!!  Thanks for the help, I'm picking up a few spares tomorrow and do some test runs tomorrow night. ??

Did you put a new plug cap on it? They can go bad eventually too. I used an NGK (they screw into the end of the plug wire) on mine. 

[Jamie Kouk]

I did but only after. I don't think the cap was the problem. It's all new now so fingers crossed it's all good for sundays race. 

[Jamie Kouk]

I have a quick question on float height. I reset mine before all this to 16mm but now it's venting fuel. Where do you guys set yours? 

[ohgood]

10 minutes ago, Jamie Kouk said:

I have a quick question on float height. I reset mine before all this to 16mm but now it's venting fuel. Where do you guys set yours? 

going by memory 17mm was my last setting. 

make sure your float needle is seating properly. if it isn't, it will leak like a seive

[OLHILLBILLY]

Be very aware of the carb body angle when setting float height. Float needle seated, but float needle spring not compressed. I can't remember exactly what I set mine at, but 17mm sounds familiar. PWKs can be pretty finicky about their float height settings, even though different models require it done differently. Example.. PWK36 on my KDX wanted the float set at an angle with the spring not compressed. PWK38 on my YZ250 wants the float set at level with the spring compressed. Both have a roughly 3mm range between fuel pouring out and the bike not starting.?

[VTMTcowboy]

year: 2004

model- 200 or 220: 200

conditions where you ride- altitude and temp: 1,000-4,000 elevation. 50-90 degrees F. 

engine modifacations you have done: None

pilot jet: 42

main jet: 155

needle number/type and clip position: Stock needle and position

air screw turns out: 2-2.5

hows it working for you? The bike runs great, mostly riding in 2nd/3rd gear, slower more technical terrain.  Never fouls plugs and starts easy, but spooging a little too much on the swing arm.  Will probably try a 40 pilot next time out to see if that helps.  When I went from stock 48 to 42 it made a huge difference, but that was at close to sea level.  Hopefully the 40 will do the trick.  I know this is more of a data base, but any suggestions?  Should I go down to a 152 on the main?  Not really worried about top end, just want the bottom-mid to be strong.  Thanks.

[Boxfresh25]

Year: 2004

Model: 220

Conditions: Florida - Sea level - 80-98 Deg - Humidity 70-90% 

Mods: RB Carb - Head - DF3 - No air box lid - 50:1

Pilot: 38

Main: 152

Needle: Cek #2 

Airscrew: First SS 1.5 - 1.75 - SSS 2.5 - 2. 7/8

hows it working for you: It's Bananas 

Edited September 22, 2018 by Boxfresh25
typo

[hi_im_sean]

Good way to ruin a thread guys. This is data collection, stop having conversations in here. If you need to trouble shoot, start your own damn thread.

[Timmae]

95 KDX200

FMF Gold Pipe

FMF Turbine Core Spark Arrestor

Boyeson Reeds

Elevation:  6500 ft. to 9000 ft.

Mountain Trail Riding - Fireroads to gnarly single track

Temp:  Pretty freeking cold to freakin hot

Jets: 150/42

Top Notch on needle - Stock needle I think

Mixture Screw: 1/2 to 1 turn

Golden Spectre at 52:1 ratio

Runs great from idle to WFO after I completely rebuilt the carb.  Everything in it is new.  Including floats, float needle, jets, jet block gasket/o-rings, bowl o-ring gasket.  Only thing I didn't replace was the needle itself and the slide.  Set up per Jeff Fredette.

Edited May 29, 2019 by Timmae

[zig06]

2002

220

About 1,000 ft elevation, jetting was completed on a 70 deg (F) day.

Stock engine, FMF Gnarly with FMF Turbinecore 2 silencer, airbox lid removed

pilot jet - 45

main jet - 155

JD Jetting "red" needle, clip set on the 4th position down

air screw - 3/4 turns out

(note:  this is richer on the pilot from JD's recommendation as they recommend only removing the snorkel where as I totally removed the airbox lid)

Seems to pull really strong off the bottom and through the mid range, will actually pull a gear higher than stock and even over what you would think this bike should be able to.  However, these are not top end screamers and this combination does flatten out on the top end.  If you want it to scream in the upper rpm's then you will need to do some head, port and carb modifications.  Even so I am very happy with the way it's running now.

[couchtater]

1993 KDX 200

5400' elevation: I ride anywhere from 4500-9000 however I have not ridden anywhere except around my home for testing. 

65° F 

Keihin PWK Airstriker Quad vent(brand new from Sudco)

FMF K14 pipe and FMF turbinecore SA

Boyesen RAD Valve

Mild porting 

Airbox lid removed and holes drilled, UNI filter

91 premium mixed with VP110, Maxima Castor 927 / 44:1

Pilot: 40

Main: 152

Needle R1173n , middle clip

Slide cutaway: 4.5 

I may try a #5 slide as it is still a bit rich on the idle, so rich the bike won't idle for more than 10 seconds. It runs excellent as is so maybe not. 

No smoke, no spooge, I am quite pleased with how this bike is running. It is very 4 stroke like in it power delivery. 

 

 

Edited November 2, 2019 by couchtater

[jrsmit11]

2002 KDX220

Riding in south Louisiana 0-600 sea level.
50-100 degrees summer time high humidity

Just recently purchased, 1st 2 stroke.
No mods to air box
MJ 145
PJ42
Needle clip is in 2nd position

Air screw 1 1/4 turns out

I need some help with the air screw part Anyone know where about I should be running the air screw with this setup?? I just don’t wanna get lean and cause damage. Would a smaller pj down to 40 cause 0-1/4 throttle openings to be a little less snappy?

[Jeeper_Jay]

2003 KDX220

Elevation Utah - Average 4200-6500 ft, occasionally up to 8500 ft.

No air box lid/snorkel

Pro Circuit full exhaust

33mm stock carb (for now - I have a brand new 35mm in the box for some day)

40:1 mix

Clip middle position stock needle

Float set at 16mm

MJ 140

Pilot 40

Air screw - 3/4 turns out

Runs pretty good bottom to top

[dmills68]

2001

model 220

Montana, 3000-8000ft   55-90 deg

fresh build/ pwk35 airstriker/ airbox snorkel and lid removed/FMF Fatty/Powercore/torque ring

pilot jet 42

main jet 150

jd jet red #2 slot

air screw 2 turns out

50:1 Amsoil Sabre

hows it working for you? great bottom and mid to top...typical little flat up top but not much.

someone make this a sticky!!!

Edited May 17, 2020 by dmills68

[Davey817]

I've got an 03 200,,,  it has 1174 needle on 3rd groove. 160 /45... Spooge running out muffler and seems to smoke quite a bit. 1173 will lean out the middle? Seems crisp down low, not too impressed in middle or top. Now the part that baffles me, throttle sticks sometimes when you go over a bump or jump. Upper end of cable and hand grip are free. It's sticking at the carb. New cable works perfectly. Got free play.  I'm thinking it has something to do with the brass tube connection on the carb cap.